The present invention relates to a method for interchanging n partial bands, or channels, of a signal frequency band.
Such methods are disclosed, for example, in German Offenlegungsschrift [Laid-Open Application] No. 2,652,607. When interchanging partial frequency bands, the complete signal frequency band is subdivided at the transmitting end into a plurality of equal-width, i.e. equal frequency range, partial bands which are interchanged by means of frequency converters. The interchange is controlled by a quasi random generator. At the receiving end the interchange is reversed with the aid of a generator which furnishes the same quasi random sequence.
The prior art band interchange method requires modulators.